A preliminary analysis of composition and structure of intestinal microbiota in patients with liver cirrhosis or hepatocellular carcinoma

Objective To investigate the differences in intestinal microbiota between patients with liver cirrhosis and those with hepatocellular carcinoma ( HCC) complicated by liver cirrhosis, as well as the association between the change in intestinal microbiota and the development of HCC. Methods A total of 35 patients with chronic liver diseases who were hospitalized in Department of Hepatology in Tianjin Third Central Hospital from December 2015 to May 2016 were enrolled, among whom 20 patients had liver cirrhosis ( liver cirrhosis group) and 15 had HCC complicated by liver cirrhosis ( HCC group) . Fecal samples were collected from all patients, total bacterial DNA was extracted, and Roche 454 sequencing was used to determine the sequence of the V3-V6 viable regions of 16 S r DNA. A bioinformatics analysis was also performed ( species taxonomy, abundance analysis, and diversity analysis) . The t-test was used for comparison of continuous data between groups, and the Mann-Whitney U test was used for comparison of categorical data between groups. Results The mean number of operational taxonomic units ( OTUs) in the samples from the 20 liver cirrhosis patients was 306. 50 ±163. 76, and that in the samples from the 15 HCC patients was 357. 24± 168. 85; there were no significant differences in the number of OTUs and alpha diversity between the two groups of patients ( both P >0. 05) . The bacteria in fecal samples included Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Genus-species and composition analyses showed that there was a significant difference in relative abundance of various bacteria in the intestine between the liver cirrhosis group and the HCC group, and compared with the HCC group, the liver cirrhosis group had significant increases in the proportions of Actinobacteria ( 0. 21% vs 0. 06%, U =89. 000, P =0. 043) , Bifidobacterium ( 0. 16% vs 0. 04%, U =90. 000, P =0. 046) , and Clostridium ( 0. 13% vs 0. 08%, U = 90. 000, P = 0. 046) and significant reductions in the proportions of Rikenellaceae ( 0. 58% vs 2. 30%, U = 82. 000, P = 0. 023) and Christenellaceae ( 0. 01% vs 0. 08%, U = 84. 500, P = 0. 028) . Conclusion There are significant differences in the composition of intestinal microbiota between patients with liver cirrhosis and those with HCC complicated by liver cirrhosis, while the specific mech anisms of the interaction between the differences and HCC with liver cirrhosis remained unclear.